Acquired immunodeficiency syndrome (AIDS) is the result of infection by HIV. It remains a major medical problem, with an estimated 34 million people infected worldwide at the end of 2011, 3.3 million of them under the age of 15. In 2011, there were 2.5 million new infections, and 1.7 million deaths from complications due to HIV/AIDS.
Current therapy for HIV-infected individuals consists of a combination of approved anti-retroviral agents. Over two dozen drugs are currently approved for HIV infection, either as single agents or as fixed dose combinations or single tablet regimens, the latter two containing 2-4 approved agents. These agents belong to a number of different classes, targeting either a viral enzyme or the function of a viral protein during the virus life cycle. Thus, agents are classified as either nucleotide reverse transcriptase inhibitors (NRTIs), non-nucleotide reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), integrase inhibitors (INIs), or entry inhibitors (one, maraviroc, targets the host CCR5 protein, while the other, enfuvirtide, is a peptide that targets the gp41 region of the viral gp160 protein). In addition, a pharmacokinetic enhancer with no antiviral activity (cobicistat) has recently been approved for use in combinations with antiretroviral agents (ARVs) that require boosting.
Despite the armamentarium of agents and drug combinations, there remains a medical need for new anti-retroviral agents, due in part to the need for chronic dosing to combat infection. Significant problems related to long-term toxicities are documented, creating a need to address and prevent these co-morbidities (e.g. CNS, CV/metabolic, renal disease). Also, increasing failure rates on current therapies continue to be a problem, due either to the presence or emergence of resistant strains or to non-compliance attributed to drug holidays or adverse side effects. For example, despite therapy, it has been estimated that 63% of subjects receiving combination therapy remained viremic, as they had viral loads >500 copies/ml (Oette, M, Kaiser, R, Däumer, M, et al. Primary HIV Drug Resistance and Efficacy of First-Line Antiretroviral Therapy Guided by Resistance Testing. J Acq Imm Def Synd 2006; 41(5):573-581). Among these patients, 76% had viruses that were resistant to one or more classes of antiretroviral agents. As a result, new drugs are needed that are easier to take, have high genetic barriers to the development of resistance and have improved safety over current agents. In this panoply of choices, novel MOAs that can be used as part of the preferred HAART regimen can still have a major role to play since they should be effective against viruses resistant to current agents.
Certain therapeutic compounds have now been set forth in WO 2013/006738, WO 2014/110298, and WO 2014/134566.
What is now needed in the art are additional compounds which are novel and useful in the treatment of HIV. Additionally, these compounds should provide advantages for pharmaceutical uses, for example, with regard to one or more of their mechanisms of action, binding, inhibition efficacy, target selectivity, solubility, safety profiles, or bioavailability. Also needed are new formulations and methods of treatment which utilize these compounds.